//epoll test program
//       
// a simple echo server using epoll in linux      
//       
// 2009-11-05      
// by sparkling      
//       
#include <sys/socket.h>      
#include <sys/epoll.h>      
#include <netinet/in.h>      
#include <arpa/inet.h>      
#include <fcntl.h>      
#include <unistd.h>      
#include <stdio.h>      
#include <errno.h>      
#include <iostream>      
#include <string.h>
#include <stdlib.h>

using namespace std;    

#define MAX_EVENTS 500      

struct myevent_s    
{    
    int fd;    
    void (*call_back)(int fd, int events, void *arg);    
    int events;    
    void *arg;    
    int status; // 1: in epoll wait list, 0 not in      
    char buff[128]; // recv data buffer      
    int len;    
    long last_active; // last active time      
};    

// set event      
void EventSet(myevent_s *ev, int fd, void (*call_back)(int, int, void*), void *arg)    
{    
    ev->fd = fd;    
    ev->call_back = call_back;    
    ev->events = 0;    
    ev->arg = arg;    
    ev->status = 0;    
    ev->last_active = time(NULL);    
}    

// add/mod an event to epoll      
void EventAdd(int epollFd, int events, myevent_s *ev)    
{    
    struct epoll_event epv = {0, {0}};    
    int op;    
    epv.data.ptr = ev;    
    epv.events = ev->events = events;    
    if(ev->status == 1){    
        op = EPOLL_CTL_MOD;    
    }    
    else{    
        op = EPOLL_CTL_ADD;    
        ev->status = 1;    
    }    
    if(epoll_ctl(epollFd, op, ev->fd, &epv) < 0)    
        printf("Event Add failed[fd=%d]\n", ev->fd);    
    else    
        printf("Event Add OK[fd=%d]\n", ev->fd);    
}    

// delete an event from epoll      
void EventDel(int epollFd, myevent_s *ev)    
{    
    struct epoll_event epv = {0, {0}};    
    if(ev->status != 1) return;    
    epv.data.ptr = ev;    
    ev->status = 0;    
    epoll_ctl(epollFd, EPOLL_CTL_DEL, ev->fd, &epv);    
}    


int g_epollFd;    

myevent_s g_Events[MAX_EVENTS+1]; // g_Events[MAX_EVENTS] is used by listen fd      

void RecvData(int fd, int events, void *arg);    

void SendData(int fd, int events, void *arg);    

// accept new connections from clients      
void AcceptConn(int fd, int events, void *arg)    
{    
    struct sockaddr_in sin;    
    socklen_t len = sizeof(struct sockaddr_in);    
    int nfd, i;    
    // accept      
    if((nfd = accept(fd, (struct sockaddr*)&sin, &len)) == -1)    
    {    
        if(errno != EAGAIN && errno != EINTR)    
        {    
            printf("%s: bad accept", __func__);    
        }    
        return;    
    }    
    do    
    {    
        for(i = 0; i < MAX_EVENTS; i++)    
        {    
            if(g_Events[i].status == 0)    
            {    
                break;    
            }    
        }    
        if(i == MAX_EVENTS)    
        {    
            printf("%s:max connection limit[%d].", __func__, MAX_EVENTS);    
            break;    
        }    
        // set nonblocking      
        if(fcntl(nfd, F_SETFL, O_NONBLOCK) < 0) break;    
        // add a read event for receive data      
        EventSet(&g_Events[i], nfd, RecvData, &g_Events[i]);    
        EventAdd(g_epollFd, EPOLLIN|EPOLLET, &g_Events[i]);    
        printf("new conn[%s:%d][time:%ld]\n", inet_ntoa(sin.sin_addr), ntohs(sin.sin_port), g_Events[i].last_active);    
    }while(0);    
}    

// receive data      
void RecvData(int fd, int events, void *arg)    
{    
    struct myevent_s *ev = (struct myevent_s*)arg;    
    int len;    
    // receive data      
    len = recv(fd, ev->buff, sizeof(ev->buff)-1, 0);      
    EventDel(g_epollFd, ev);    
    if(len > 0)    
    {    
        ev->len = len;    
        ev->buff[len] = '\0';
        printf("C[%d]:%s\n", fd, ev->buff);    
        // change to send event      
        EventSet(ev, fd, SendData, ev);    
        EventAdd(g_epollFd, EPOLLOUT|EPOLLET, ev);    
    }    
    else if(len == 0)    
    {    
        close(ev->fd);    
        printf("[fd=%d] closed gracefully.\n", fd);    
    }    
    else    
    {    
        close(ev->fd);    
        printf("recv[fd=%d] error[%d]:%s\n", fd, errno, strerror(errno));    
    }    
}    

// send data      
void SendData(int fd, int events, void *arg)    
{    
    struct myevent_s *ev = (struct myevent_s*)arg;    
    int len;    
    // send data      
    len = send(fd, ev->buff, ev->len, 0);    
    ev->len = 0;    
    EventDel(g_epollFd, ev);    
    if(len > 0)    
    {    
        // change to receive event      
        EventSet(ev, fd, RecvData, ev);    
        EventAdd(g_epollFd, EPOLLIN|EPOLLET, ev);    
    }    
    else    
    {    
        close(ev->fd);    
        printf("recv[fd=%d] error[%d]\n", fd, errno);    
    }    
}
 
void InitListenSocket(int epollFd, short port)    
{    
    int listenFd = socket(AF_INET, SOCK_STREAM, 0);    
    fcntl(listenFd, F_SETFL, O_NONBLOCK); // set non-blocking      
    printf("server listen fd=%d\n", listenFd);    
    EventSet(&g_Events[MAX_EVENTS], listenFd, AcceptConn, &g_Events[MAX_EVENTS]);    
    // add listen socket      
    EventAdd(epollFd, EPOLLIN|EPOLLET, &g_Events[MAX_EVENTS]);    
    // bind & listen      
    sockaddr_in sin;    
    bzero(&sin, sizeof(sin));    
    sin.sin_family = AF_INET;    
    sin.sin_addr.s_addr = INADDR_ANY;    
    sin.sin_port = htons(port);    
    bind(listenFd, (const sockaddr*)&sin, sizeof(sin));    
    listen(listenFd, 5);    
}

 
int epoll_test(int argc, char **argv)    
{    
    short port = 12345; // default port      
    if(argc == 2){    
        port = atoi(argv[1]);    
    }    
    // create epoll      
    g_epollFd = epoll_create(MAX_EVENTS);    
    if(g_epollFd <= 0) printf("create epoll failed.%d\n", g_epollFd);    
    // create & bind listen socket, and add to epoll, set non-blocking      
    InitListenSocket(g_epollFd, port);    
    // event loop      
    struct epoll_event events[MAX_EVENTS];    
    printf("server running:port[%d]\n", port);    
    int checkPos = 0;    
    while(1){    
        // a simple timeout check here, every time 100, better to use a mini-heap, and add timer event      
        long now = time(NULL);    
        for(int i = 0; i < 100; i++, checkPos++) // doesn't check listen fd      
        {    
            if(checkPos == MAX_EVENTS) checkPos = 0; // recycle      
            if(g_Events[checkPos].status != 1) continue;    
            long duration = now - g_Events[checkPos].last_active;    
            if(duration >= 60) // 60s timeout      
            {    
                close(g_Events[checkPos].fd);    
                printf("[fd=%ld] timeout[%ld--%ld].\n", g_Events[checkPos].fd, g_Events[checkPos].last_active, now);    
                EventDel(g_epollFd, &g_Events[checkPos]);    
            }    
        }    
        // wait for events to happen      
        int fds = epoll_wait(g_epollFd, events, MAX_EVENTS, 1000);    
        if(fds < 0){    
            printf("epoll_wait error, exit\n");    
            break;    
        }    
        for(int i = 0; i < fds; i++){    
            myevent_s *ev = (struct myevent_s*)events[i].data.ptr;    
            if((events[i].events&EPOLLIN)&&(ev->events&EPOLLIN)) // read event      
            {    
                ev->call_back(ev->fd, events[i].events, ev->arg);    
            }    
            if((events[i].events&EPOLLOUT)&&(ev->events&EPOLLOUT)) // write event      
            {    
                ev->call_back(ev->fd, events[i].events, ev->arg);    
            }    
        }    
    }    
    // free resource      
    return 0;    
}  
